Chagas disease is the most serious parasitic disease and a leading cause of heart disease in Latin America. It has been difficult to control in Central America and Mexico since the main species of insect that spreads the parasite, Triatoma dimidiata, is found in forests and as well as areas surrounding houses and readily re-colonizes houses after fumigation. In addition, although T. dimidiata specimens look similar across their geographic range, preliminary data suggest the species may include distinct taxa. The long-term goal of this research is to understand the influence of environmental and genetic interactions on the transmission of Chagas disease. As the first step, the taxonomic status of Triatoma dimidiata populations, the main Chagas disease vector in Central America, will be determined. Taxonomic diversity can manifest itself and affect disease transmission in several ways. We focus on understanding the degree of morphological variation;diversity in the sequence and organization of DNA in chromosomes;and epidemiological differentiation (blood source, T. cruzi infection, preferred habitat) among T. dimidiata populations from distinct geographical localities and across a range of ecological habitats. The results of this research will indicate the dividing lines among genetically distinct taxa, and will identify the taxa most likely to transmit Chagas to humans. As one of our collaborators works closely with the Guatemalan Ministry of Health and the WHO Central American Initiative against Chagas disease, the information obtained will be put immediately to use into the control efforts. In addition, through this work we will train undergraduate students from the U.S. and endemic countries to enhance the scientific workforce needed by the public sector, academia and industry. PUBLIC HEALTH RELEVANCE Chagas disease is a leading cause of heart disease and the most serious parasitic disease in Latin America. To help halt transmission of this disease, we will study the genetics of the main insect vector that transmits Chagas in Central America. This will allow us to identify which populations of insects are responsible for most of the Chagas transmission in this region and develop control efforts targeting these insects.